Function of over hoist limit switch is to prevent the over run of the cradle and hitting the suspension mechanism. When the limit switch level touches upper end, power supply to electrical motor gets stopped.

Electromagnetic Brake with manual release:

Hoist motor is provided with electromagnetic brake as primary holding device. Manual release mechanism shall help the cradle to be lowered to the ground level in case of power failure.

Over current protection thro' Relay (OLR):

This will be part of electrical control system. If the electrical motor draws beyond rated current due to overloading, this protection device will cut-off the electrical system.